Prvomajska G301 Milling machine converting to CNC

Hello All!

More than10 years ago (at that time i just started my studies) my father found a great milling machine in a scrapyard, Prvomajska G301 D1 manufactured in 1973 , the machine seems to be almost not used at all, unfortunately it was subject to weather changes and most of the axis were locked up by rust, its spindle motor and holding bracket broken off and x axis gearbox with motor broken off. Back when he brought it home we started to disassemble, we removed some parts from its quill and then life happened we left it on the field covered with plastic sheets as there was no more space on the workshop. 
Recently we removed some things from the shop and got some place for the mill and we placed it inside, past week we were working very hard to clean up the rest of the machine and mount it back, so far the worst part is that its spindle bearing are quite rusty and once we get the rest sorted out will have to be replaced (altho, i still dont know where we could find it).

Attached are images of before and after cleanup and a picture of a machine we found online.

Couple of decisions weve come up with so far regarding the mechanical parts are as following:
Z-Axis: The Z-Axis has 36mm trapezoidal screw moved through bevel gears from the handle and the nut is bolted on the base of the machine offset by an iron piece, maybe can be seen from a picture when the saddle traverse was removed. Since we couldnt find a neat way to put a ball screw, also, were assuming the ball screw having less friction forces the z axis will just fall down, weve decided to leave the original screw and return back to it if we find any issue later on, following This Old Tony's conversion of his Maho and leaving its Z axis with trapezoidal screw, we're expecting the same...
X/Y-Axis: Both have 28mm trapeziodal screws with anti-backlash nut with pitch of 5mm. The nuts hole on the casting for both sides is 40mm which to our research matches the 25mm ballscrew so it is more or less the driving factor to chose 25mm ballscrews.

Issue #0: Throughout this project we always find it challenging to transport anything to place where we live due to some political issues and locally there is no store that sells parts. One of the solution we've found is a middleman in Germany that transports things to here so more or less we always have to check for delivery to Germany and goods that arent subject to VAT...

Question #1: We plan to travel to a nearby country that has ballscrews however im a little bit confused by Dynamic load rating and Static load rating related to price. A low price offers C(dyn) ~ 1100kgf and C(0) ~ 2700kgf, while a 5 times the low price C(dyn) ~ 1700kgf and C(0) ~ 5000kgf, but a 6 times the low price we can get a C(dyn) ~ 14900kgf and C(0) ~ 41500kgf... I'd appreciate a suggestion if going with the low price option is sufficient, as the 5 times the price seems to not gain much for the added cost and the last option seems like a straight up overkill.. 

Question #2: For the Motors to drive the axis of the machine, were planning to place stepperonline servo motors rated at 1kW ( link ) but interestingly they seem to have EtherCAT servos as well so im  kinda on a edge here.. I was originally planning to go with mesa cards prior to seeing the EtherCAT options, but now i kinda dont mind the added cost for EtherCAT, however, my father hopes to use the machine as a manual mill but he isnt very technophile so we will have to add quite some buttons and dials rather than use the keyboard/mouse to control the machine manually and for this we will need some IO, so, is there any EtherCAT IO that i can daisy chain to the system? I have no experience with EtherCAT so i dont know what im getting into... does LinuxCNC need to support the mentioned drive? Do we have to expect support from the manufacturer for the application? Is it doable?

Question #3: If i was to go with normal drives, i cant really decide on the loop's of the system and therefore the cards. I dont have any experience with Mesa cards, but i do have some experiences with parallel port LinuxCNC and Raspberry GPIO LinuxCNC. Should i go straight to position loop on mesa cards and velocity loop on the drive (hence analog mesa cards) or shall i take it slow and get a step/dir card and later on get an analog card if im happy with it?
Question #3.1:This leads to does Mesa official store shipment to Germany include VAT and complicated transportation or is it simple drop off?
Question #3.2: Can you suggest a good card match up for 4 Axis movement + Spindle + Lots of IO for control panel?

Question #4: Since Servos offer modbus and you can read the position of its absolute encoder im assuming that you can skip the homing procedures on LinunxCNC and fetch position from drives directly, am i correct? 

Question #5: How important is spindle encoder for a milling machine? I cant seem to find a proper place to seat it...

Any suggestion, question or comment welcomed! 

Thanks in advance!